In the operation of a hydraulic, adjustable axial piston pump, mechanical energy is converted to hydrostatic energy. The mechanical energy is supplied, for example, by an electric motor. In the structure of an axial piston pump, hydraulic pumps of this type normally have numerous cylinders, which are attached to a rotatable shaft such that they extend in the axial direction, and are disposed on a partial circle, offset at a radius to the shaft axis. Pistons are displaceably disposed in the cylinders. The pistons, which rotate with the cylinder, are moved, for example, by an adjustable inclined plate. For this movement, in order to minimize the friction, a piston/sliding shoe connection is provided between the inclined plate and the pistons.
One problem of conventional axial piston pumps is the mass of the rotating piston, which is normally made of a single piece. Because of this mass, significant energy is needed to accelerate the piston, and to subsequently decelerate it, this energy being associated with significant wear in the region of the piston/sliding shoe connection. In order to reduce the inertia of the mass, a bore hole has been provided previously, in the base of the piston, such that the piston is substantially hollow. A bore hole of this type in the piston has the disadvantage, however, that the dead volume in the cylinder is increased. As a result of the dead volume, there are compression losses and increased volume flow, or pressure, fluctuations, which are a reflection of a lower pumping efficiency.